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International Journal of Antennas and Propagation
Volume 2013 (2013), Article ID 528950, 9 pages
http://dx.doi.org/10.1155/2013/528950
Research Article

An Antenna Measurement System Based on Optical Feeding

Optics and Electronics Laboratory, Fujikura Ltd., Sakura-shi 285-8550, Japan

Received 30 January 2013; Revised 29 March 2013; Accepted 31 March 2013

Academic Editor: Sara Burgos

Copyright © 2013 Ryohei Hosono and Ning Guan. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A radiation measurement system by using optical feeding is proposed. The system replaces conventional electrical feeding to antennas by the optical feeding which is composed of an electrical/optical (E/O) converter, a graded-index (GI) optical fiber, and an optical/electrical (O/E) converter. The GI fiber is used so as the O/E converter becomes very compact by using a simple means of coupling between the fiber and the photo-diode in the converter. A vertical surface emitting laser (VCSEL) is used in the E/O converter to make the system available till 6 GHz. This combination also makes the system cost-effective. The validity as well as the advantage of the system is demonstrated by measuring an ultra-wideband (UWB) antenna both by the optical and electrical feeding systems and comparing with a calculated result. Ripples in radiation pattern due to the electrical feeding are successfully suppressed by the optical feeding. For example, in a radiation measurement on the azimuth plane at 3 GHz, ripple amplitude of 1.0 dB that appeared in the electrical feeding is reduced to 0.3 dB. In addition, a circularly polarized (CP) antenna is successfully measured by the proposed system to show that the system is available not only for amplitude but also phase measurements.